Inter-day Test-retest Reproducibility of the CAT, CCQ, HADS and EQ-5D in Patients With Severe and Very Severe COPD

Abstract Background In patients with COPD the COPD Assessment Test (CAT), Clinical COPD Questionnaire (CCQ), Hospital Anxiety and Depression Scale (HADS) and EuroQol 5D (EQ-5D) are widely used patient reported outcome measures (PROMs) of respiratory symptoms, anxiety, depression and quality of life. Despite established responsiveness and minimal important change (MIC), reproducibility and especially important agreement parameters remain unreported in these frequently used PROMs. The aim of this study was to investigate the inter-day test-retest reliability and agreement of the CAT, CCQ, HADS and EQ-5D in patients with severe and very severe COPD (FEV1 <50%) eligible for hospital-based pulmonary rehabilitation. Patients and Methods Fifty patients (22 females, mean [SD] age 67 [9] yrs.; FEV 1 32[9] %; 6-minute walk distance 347 [102] meters; CAT 21 [6] points; BMI: 26 [6] kg/m 2 ) completed the questionnaires (CAT, CCQ, HADS, EQ-5D) in combination with functional performance test instructed by one assessor on test-day one (T1) and by another assessor 7-10 days later on test-day two (T2). Results The inter-day test-retest reliability ICC was 0.88 (LL 95CI : 0.80) for CAT; 0.69 (LL 95CI : 0.46) for CCQ; 0.86 (LL 95CI : 0.75) and 0.90 (LL 95CI : 0.82) for HADS-anxiety (A) and depression (D) and 0.87 (LL 95CI : 0.76) for EQ-5D-VAS. The corresponding agreements within a single measurement (standard error of measurement, SEM) and for repeated measurement errors (smallest real difference, SRD) were respectively 2.1 and 2.9 points for CAT; 0.5 and 0.7 points for CCQ total; 1.3 and 1.9 points for HADS-A; 0.9 and 1.3 points for HADS-D) and 6.8 and 9.7 VAS-score for EQ-5D respectively. Ceiling/flooring effect was present in <5% for all questionnaires. Conclusion In patients with severe and very severe COPD the CAT, CCQ, HADS and EQ-5D questionnaires presented moderate to excellent inter-day test-retest reliability and acceptable agreement e.g. SEM and SRD below the established MIC on group level except for the CCQ questionnaire. No floor or ceiling effect of relevance was documented for the questionnaires.